Realization of non-polar ZnO (1120) homoepitaxial films with atomically smooth surface by molecular beam epitaxy

摘要

A route for realizing non-polar ZnO (1200) films with atomically smooth surface is demonstrated by employing rf-plasma assisted molecular beam epitaxy on ZnO bulk substrates. It is found that high growth temperature plays an important role in suppressing the typical striped structure along ZnO [0001] direction on non-polar planes. An atomically smooth surface with a root mean square roughness of 0.51 nm that is suitable for fabrication of quantum wells is achieved after solving the growth anisotropy problem, as confirmed by the combined studies of reflection high-energy electron diffraction and atomic force microscopy.